Antenna



June 12, 1934. R, L. MEREDITH ANTENNA Filed Oct. 30, 1929 2 Sheets-Sheet l June 12, 1934. R. l.. MEREDI'TH ANTENNA Filed Oct. 30, 1929 2 Sheets-Sheet 2 Patented June 12, 1934 UNITED STATES PATENT OFFICE ANTENNA America, New York, Delaware Application October 30,

6 Claims.

This'invention relates to an antenna and particularly to an antenna mast for use on aircraft.

Following the development of radio receivers of high sensitivity it has been possible to emplo-y the vertical rod type of antenna on aircraft in place of a trailing wire antenna, but the cylindrical rods or tubes which have been used are open to a number of serious objections; the principal ones being the weight of the structure, the tendency towards vibration and the high` wind resistance.

Objects of the invention are to provide antenna structures which may be readily secured to aircraft of various types, which are of light weight and which offer a relatively low wind resistance.

' 15 More specifically, an object is to provide an antenna mast of streamline cross-section which is of progressively decreasing cross-section from its attached towards its free end. A further object is to provide an antenna of the type last stated which is particularly free from vibration. f

These and other objects of the invention will be apparent from the following specification when taken with the accompanying drawings in which: Y

Fig. 1 is an elevation, as viewed obliquely from the rear, of one embodiment of the invention,

Fig. 2 is a fragmentary vertical section through the same, as taken on the plane of line 2-2 of Fig, 3,

Fig. 3 is an enlarged fragmentary vertical section taken at right angles to Fig. 2,

Fig. 4 is a transverse section on line 4--4 of Fig. 3,

Fig. 5 is a fragmentary perspective View of the interior elements of the antenna mast,

Figs. 6 and 7 are, respectively, side and front elevations of another embodiment of the invention,

Fig. 8 is a fragmentary central section on the f vertical plane of symmetry of the mast,

Fig. 9 is a fragmentary vertical section at right angles to Fig. 8, and

Fig. 10 is a transverse section through the interior elements of the mast.

As shown in the drawings, the mast has the form of a tapering body which is of streamline cross-section throughout its length, and includes a base plate l having a depending cylindrical portion 2 for reception in a tubular socket member 3. The upper face of the base plate has an integral tubular boss 4 of streamline cross-section, the upper edge of the boss being notched at opposite sides and substantially on the axial plane of the depending portion 2 to receive the shoulders 5 of a bar 6. The bar 6 is rigidly secured N. Y., a corporation of 1929, Serial No. 403,546

(Cl. Z- 33) within the boss by a transverse screw 7 and by expanding the lower end of bar 6, for example, by striking the same, as indicated at 8, with a cold chisel or the like.

The upper end of bar 6 is slightly tapered and a tapered channel member 9 is connected to the same by rivets 10, the side flanges of the channel being ush with the cuter edges of shoulders 5 and with the side walls of the boss 4.

A metal shell 1l of streamline cross-section encloses the boss 4 and channel 9, and conforms closely to the same in order that the shell and inner member may mutually reinforce each other. As best shown in Figs. 1 and 4, the shell 1l coinprises a single sheet of metal which is bent about the boss 4 and channel 9; the lap weld l2 which unites the adjacent flanges of the sheet being located at the rear of the mast. A plurality of rivets 13 pass laterally through the shell ll and boss 4 to provide a rigid assembly.

A plate 14 of insulating material is tted over the mast adjacent the upper end thereof and the forward edge of the plate has perforations 15 for receiving guy wires.

With the exception of the plate 14, the parts of the mast are of metal, preferably aluminum or an aluminum alloy. The socket 3 may be given any desired or convenient form when the mast is to be mounted upon a given type of aeroplane, but for general application to planes of dierent construction, I have found it convenient to form the socket member 3 as a relatively long aluminum tube which may'then be cut to any convenient length for connection to the fuselage of a particular plane.

The mast illustrated in Figs. 6 to l0, inclusive, has the same tapering streamline form, but in this embodiment the surface of the mast is of an electrically insulating material. In this form the base plate 20 has a tubular depending portion 21 for reception in a cylindrical socket, and the upper face of the plate has opposed projections 22 which receive between them the web of a tapered I-member that may, as illustrated, take the form of two channels 23.

The projections 22 are reinforced by ribs 24 and rivets 25 are passed through the projections to secure the channels in place. Additional rivets 26 pass through the upper portion of the channels to unite them in I-form, and the channels are provided with a series of perforations 26.

The enclosing shell 28 which provides the tapered streamline cross-section is formed of an electrically insulating material which may be,

CTI

Cil i and preferably is molded in situ upon the base plate and channels.

I preferably employ a cellular composition which, as indicated by the stippling on the drawings, is relatively dense and imperforate at portions which contact with the mold and the metal of the mast while the interior portions of the composition are relatively light, the cells in these portions being of somewhat larger size. The molded composition resembles a sponge rubber of minute cells, but is characterized by a more complete vulcanization which gives the dense exterior surfaces substantially the properties of hard rubber.

While both of the forms which I have described reduce the tendency towards vibration due to the reduced wind resistance, the body of insulating material effects a further reduction of vibration due to the damping action of the molded shell. The molded shell has the additional advantage that electrically charged rain drops striking the insulating shell do not give rise to the static effects which are noticed when the antenna has an exposed conducting surface.

It will be apparent that the invention is not limited to the particular constructions which are herein illustrated and described as various changes may be made in the several parts, their relative size, shape and relation without departing from the spirit of my invention as set forth in the following claims.

I claim:

l. An aircraft antenna comprising a mast, a fuselage supporting base plate having a depending cylindrical portion for the reception of a tubular socket member, an upwardly extending boss integral with said supporting base plate, a metallic channel member secured to said boss, insulating material of cellular composition molded around said channel member, said insulating material having a tapering streamline contour to offer a relatively low wind resistance.

2. An aircraft antenna comprising a mast, a fuselage supporting base plate having a depend ing cylindrical portion for the reception of a tubular socket member, an upwardly extending boss integral with said supporting base plate, a metallic channel member secured to said boss, electrically insulating material of cellular composition whose interior portion comprises cells of relatively larger area than the exterior portion which surface presents a more dense surface having substantially the properties of hard rubber.

3. An aircraft antenna comprising a mast, a fuselage supporting base plate having a depending cylindrical portion for the reception of a tubular socket member, an upwardly extending boss integral with said supporting base plate, a central metallic tapering I-member secured to said boss, electrically insulating material of cellular composition whose interior portion comprises cells of relatively larger area than the exterior portion which surface presents a more dense surface having substantially the properties of hard rubber.

4. An aircraft antenna comprising a mast, a fuselage supporting base plate having a depending cylindrical portion for the reception of a tubular socket member, an upwardly extending boss integral with said supporting base plate, a central metallic tapering I-member secured to said boss, said I-member being composed of two metallic channel members secured together, said members having apertures to secure electrical insulating material of cellular composition whose interior portion comprises cells of relatively larger area than the exterior portion which surface presents a more dense surface having substantially the properties of hard rubber.

5. An aircraft antenna comprising a mast, a fuselage supporting base plate having a depending cylindrical portion for the reception of a tubular socket member, upwardly extending opposed projections having tapering webs to secure a central tapering metallic member, electrically insulating material of cellular composition Whose interior portion comprises cells of relatively larger area than the exterior portion which surface presents a more dense surface having substantially the properties of hard rubber.

6. An antenna comprising a base having means for connecting the same to the fuselage of an 1 progressively decreasing cross-section from the said base towards the free end of said shell.

RUSSELL L. MEREDITH. 

